THE COST BENEFIT OF USING UNATTENDED MONITORING SYSTEMS TO AUGMENT THE PHYSICAL INVENTORY PROCESS

Nuclear materials at DOE/NNSA facilities are currently subject to a comprehensive set of material control and accountability (MC&A) procedures that are designed to deter and detect their theft and diversion. These MC&A procedures are facility and site specific, and meet the general requirements of DOE Order O 474.1A and the accompanying Manual [1,2]. A key subset of these procedures is the physical inventory process. The physical inventory process is conducted periodically, with direct human involvement, to verify the amounts, characteristics and locations of the subject materials. Plutonium pits, stored at the Pantex Plant, are considered to be Category I nuclear material and have a mandated, semiannual inventory frequency. Exceptions to the semiannual inventorying requirement for Category I materials can be granted under certain circumstances, i.e., when the items are subject to continuous and, independently functioning monitoring measures [2]. Under these circumstances the inventory frequency is extendable, on approval, for up to 5 years. These continuous monitoring measures can include video surveillance and sensors for monitoring motion, seal integrity, temperature, and gamma and neutron emissions. While such monitoring measures are not currently deployed in Pantex pit storage magazines, explorations of their use at Pantex and at other NNSA sites with weapons fissile materials have been conducted over the past decade, driven by both domestic and international needs [3-5]. The aim of the present study is to determine if the physical inventorying costs avoided in supporting a domestic MC&A mission could, over time, offset the monitoring system’s up-front procurement and installation costs. For the system considered in this study, the continuous monitoring measures are provided by video surveillance systems, volumetric motion detection systems, and by active Electronic Sensor Platforms (ESPs) affixed to the pit storage containers that sense container motion and fiber-optic seal status. The monitoring system design and function has been described previously [5].